多頻道天線與雙工器之整合設計及低溫陶瓷共燒濾波器

Abstract

通訊系統前端的射頻元件整合模組，通常只包括雙工器與兩個不同頻段的帶通濾波器，隨著前端射頻模組的高度整合化，雙頻天線與雙工器之整合設計在未來的研究與通訊產品設計中也將是一個無可避免的趨勢。在本論文中，以Ansoft HFSS全波分析軟體作為設計之工具，提出雙頻天線和雙工器的整合設計以應用於無線區域網路 ( Wireless Local Area Netowrk，WLAN ) 系統。本文中所提出的雙頻天線結構，是將原本的四分之一波長單極天線（□/4 monopole antenna）加入袖型(sleeve)結構以達到雙頻與寬頻的效果。雙工器部份則是利用步階阻抗諧振腔帶通濾波器與四分之一波長平行耦合帶通濾波器疊加而成。sleeve雙頻天線架構在2.4 GHz與5 GHz WLAN 頻段分別具有22.49%和32.58% 的阻抗頻寬。此雙頻天線和雙工器的整合架構將能夠滿足 2.4 GHz和5.2 GHz WLAN系統的需要。此外我們選用合適帶通濾波器的集總元件電路模型，有效地利用低溫共燒陶瓷（Low Temperature Co-fired Ceramics，LTCC）製程設計出符合WLAN 2.4GHz帶通濾波器規格的帶通濾波器，以期達到體積小，高選擇性，具有高整合度的元件。

The integrated RF front-end module of communication systems usually only includes a diplexer and two different bandpass filters. As the RF front-end module becomes highly integrated, the integrated design of a dual-band antenna and a diplexer will be in great trends for research and commercial products in the future. In the paper, Ansoft HFSS full wave simulator is used to be the design tool. The purpose of this paper is to propose a new integration design of a dual-band antenna and a diplexer that can be applied to the Wireless Local Area Network (WLAN) system. The dual-band antenna structure proposed by this paper is constructed by the original quarter wavelength (□/4) monopole antenna plus a sleeve structure. This improvement is expected to help obtain the wide bandwidth and dual-band effect. The diplexer is composed of stepped impedance resonator bandpass filter and □/4 parallel coupled microstrip line bandpass filter. The proposed dual-band antenna structure possesses 22.49% and 32.58% impedance bandwidth under the WLAN band of 2.4 GHz and 5 GHz. The proposed integrated structures of the dual-band antenna and the diplexer can meet the requirements of the 2.4 GHz and 5.2 GHz WLAN systems. Besides, in order to obtain a WLAN bandpass filter with the specific of 2.4GHz, we apply LTCC to effectively process the selected suitable lumped element circuit model of the bandpass filter. The newly designed WLAN bandpass filter will be of small size, of high selectivity and highly integrated.